Method for preparing lower volume fraction porous silicon carbide ceramic body

A technology of porous silicon carbide, volume fraction, applied in the field of metal matrix composites

Inactive Publication Date: 2013-01-16
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If the viscosity of the slurry is too high, it is difficult to form the green body, and if the viscosity of the slurry is too low, it will easily cause the solid particles to settle during the gel process, and the green body will shrink too much in the later stage, resulting in serious deformation of the green body.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Embodiment 1: preparation intensity is that 3MPa, SiC volume fraction are the porous green body of 15vol%

[0018] Using silica sol with a concentration of 30% as a solvent, acrylamide (AM) as a monomer, and methylenebisacrylamide (MBAM) as a crosslinking agent, the mass fraction of the monomer is 30%, and the mass ratio of MBAM to AM is 1: 50 premix solution, silicon carbide powder with a particle size of 25 μm and graphite powder with a particle size of 3 μm were added to the above premix solution at a volume ratio of 1:2, and tetramethyl 10% amine hydroxide (TMAH) aqueous solution was used as a dispersant, and SiC and graphite powder accounted for 45% of the total volume. Use alumina as the ball milling medium and mix for 1 hour, then add 0.5% of the total volume of ammonium persulfate 8% aqueous solution (ASP) as the initiator and 0.5‰ of tetramethylethylenediamine (TEMED) as the catalyst, and stir well Inject it into the mold to form the desired shape, then plac...

Embodiment 2

[0020] Embodiment 2: the preform that preparation strength is 4MPa, SiC volume fraction is 45vol%

[0021] Using silica sol with a concentration of 20% as a solvent, acrylamide (AM) as a monomer, and methylenebisacrylamide (MBAM) as a crosslinking agent, the mass fraction of the monomer is 25%, and the mass ratio of MBAM to AM is 1: 60 premix solution, silicon carbide powder with a particle size of 20 μm and graphite powder with a particle size of 5 μm were added to the above premix solution at a volume ratio of 15:1, and at the same time 1.5% of the powder mass fraction was added. Ammonium hydroxide 10% (TMAH) aqueous solution was used as a dispersant, and SiC and graphite powder accounted for 48% of the total volume. Use alumina as the ball milling medium and mix for 1.5 hours, then add 0.6% of the total volume of ammonium persulfate 8% aqueous solution (ASP) as the initiator and 0.6‰ of tetramethylethylenediamine (TEMED) as the catalyst, and stir well Pour it into the mo...

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Abstract

The invention discloses a method for preparing a lower volume fraction porous silicon carbide ceramic body. According to the method, water in an acrylamide gel system formed by adopting a conventional ceramic gel injection molding process is replaced by silica sol to form a silica sol-acrylamide double gel network system. A gel blank is enabled to have a certain strength by controlling the ratio of the silica sol to acrylamide and adding graphite powder with a certain proportion in slurry; and meanwhile, by using a silica sol-gel network left by removing the gel, the blank is enabled to have a certain strength and the requirement of late infiltration metal on the strength of the blank body can be met. Due to the adoption of the graphite powder in the slurry, the setting phenomenon of carborundum particles due to low viscosity caused by overlow volume fraction in the gel process can be effectively avoided and the graphite powder can be burnt out in the air in the late stage of gel removal. According to the method, the porous silicon carbide ceramic body with the volume fraction being 15-45 percent, the strength being over 3MPa and the closed porosity being smaller than 0.5 percent can be prepared with lower cost.

Description

[0001] technical field [0002] The invention belongs to the research field of metal matrix composite materials, and relates to a method for preparing a low volume fraction porous ceramic green body. Background technique [0003] Low volume fraction (15~45vol%) silicon carbide particle reinforced aluminum matrix composites not only have good comprehensive mechanical properties, but also have excellent wear resistance, which is an ideal structure and wear-resistant material. However, the high hardness, high brittleness and other characteristics of this material make it difficult to process it into parts of the required shape by secondary machining, which greatly limits the wide use of this material. Therefore, it is very necessary to develop a near-net-shape process for this material. At present, the near-net shape process widely used at home and abroad is the liquid metal infiltration method, which is to prepare the porous reinforced phase ceramic body with the final shape ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/565C04B35/63C04B35/622
Inventor 任淑彬曲选辉许慧何新波章林吴茂
Owner UNIV OF SCI & TECH BEIJING
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